Smallest tubing that’s safe?

[Steve Broady]

I’ve read comments to the effect that you shouldn’t have anything smaller than 1/2” OD tubing anywhere in the vapor/product path. Anything smaller can get clogged up if the boiler pukes.

That seems like overkill to me, if we’re talking about a small (1-2 gall, for example) still, or one which is only used as a gin still. Obviously, you don’t want to throw a bunch of corn mash in, fill it up to the very top, and then try to push vapor through a 1/4” OD line. That’s dumb, and you might get what you asked for if you try it. But what about a small still that only sees clear wash? For example, I have a stainless pressure cooker that’s about a gallon, and have thought about building a small gin still. Would 3/8” OD tubing offend the safety police? Or even 1/4”?

My mini shotgun has four 1/4” tubes in it. So far, I’ve had zero issues. Of course, I built it before I read that 1/2” is the minimum allowable. I don’t think I’ll be getting rid of it though.

The reason I ask is that I’ve been toying with the idea of building another condenser. Looking at the tubing in the local hardware store, and all the fittings that go with it, the jump from 3/8” to 1/2” at least doubles if not triples the price. If that’s what safety costs, then so be it, but that 3/8” looked plenty big enough to my inexperienced eye. Left to my own devices, and with a pretty healthy respect for my own skin and long standing culture of safety, I would absolutely use 3/8” OD tube without concern.

I’d like to hear the opinions of others, though. You’ve been there, done that, seen things that I don’t want to see, and I’d be a fool not to listen.

[Salt Must Flow]

My shotgun condenser has seven 3/8" ID copper pipes. I don't foresee ever having any issues with it.

When it comes to a shotgun condenser, it's all about surface area. A shotgun that has seven 3/8" pipes will have more surface area than the same length shotgun that has four 1/2" copper pipes. There's more knockdown power per inch of condenser.

[shadylane]

My two cents worth.

Based on safety, price, and availability 1/2" ID works the best for small stills.
Bigger vapor tube diameter equals more surface area and lower vapor speed.
Why build a shotgun for a small still, when a simple liebig is more logical.

For a stove top still, here's a simple, cheap and effective condenser.
viewtopic.php?t=72748

[Steve Broady]

Why build a shotgun for a small still, when a simple liebig is more logical.

In this case, I’m thinking more along the lines of a 3/8” Liebig, coiled up into a neat little package.

As for why I built a shotgun, mostly to see if I could. I’ve got a lifelong love of steam locomotives, and figured it would be good practice for making the tube sheet and tubes for a boiler. The “practical” justification for it was that I thought I wanted a perfectly vertical condenser in order to reduce the footprint of the still, and given the height of the boiler, a shotgun was the only practical way to get the required knockdown power in the available length. Turns out that was completely pointless, but I didn’t realize that when I made the decision to build it. Live and learn.

[shadylane]

...I’m thinking more along the lines of a 3/8” Liebig, coiled up into a neat little package.

A better option would be a dimroth condenser.
With cooling water flowing through the 3/8" tubing and the vapor condensing on the outside of it.

[Steve Broady]

I need to do more research about dimroth condensers. Haven’t really thought much about them, but that does sound interesting. And I like learning new things.

[NZChris]

Every gin run I've ever done has had solids in the still that could easily block a 3/8" OD tube.

My gin still is a saucepan and steamer with flour paste seals because I want the seals to pop gently if there is a blockage.
You don't have that luxury with a pressure cooker, plus most of them have silicone seals and a pressure relief valve that would spray hot fuel into the air if it ever went off.

The copper I've used has come from scrapyards at a fraction of the price of new.

[NZChris]

Copper doesn't have a flavor advantage for the condenser of a gin still. You can buy thin walled 304 SS out of China at quite reasonable prices. 10 x 9mm, 12 x 11mm, 500mm lengths.

[StillerBoy]

I’d like to hear the opinions of others, though.

Pictured below is a 2" concentric setup in the stripping mode.. and attached is 3/8 x 10" (1/2" outter) able to stripped at 3100w with the disitillate at 80*F (room for higher output yet if wanted).. it's all how one understand what a condenser does..

Mars

[The Baker]

I had a stainless Liebig condenser. Got it for free.
It used to be a pre-cooler in a dairy.
Maybe two inch outside, one and a quarter inch inside.
Maybe five feet long (!).

I stuck a three quarter inch copper tube down the middle and re-arranged the connexions (which was tricky, got the son-in-law to do it...),
made it into a Davies condenser. Water inside, vapour next, water in the outside tube.

Much better. Closer contact of vapour with the TWO water filled tubes.
And more copper contact (there was already some in the lead-in riser and tubes of the pot still).

Geoff

[Yummyrum]

It’s a fare question Steve .
We don’t have a fixed rule about it on HD forum but we have more a best practices based on safest outcome .

It does come down to risk assessment .

If you were to run a sugar wash and only that and nothing else , then its arguable that 1/4” if it could handle the power , would be perfectly adequate as the chances of anything causing a plug is almost zero .
Infact a bank of 1/4” in a Shotty would be very capable of handling as much power as you could use if you scaled it right .

But the reality is we don’t all do sugar washes …. and even if when we start the hobby , that is our intention , things change . We do need to always be aware of the minimum size in our system :

The number one problem that comes to mind is grains causing a plug , but as As NZchris said , even a simple Gin run has the potential to be a hazard and cause a serious plug .

So looking at the grains , a swollen corn kernel will easily block a 1/4” pipe . So that rules that out straight away .

The same kernel will have no problem passing a 1/2” pipe , but 3/8” becomes a lottery .

And what if two kernels arrive at the place at the same time ???

3/8” shotty is probably better odds than a single 3/8” worm or liebig .

How many random kernels will it take to fully block a 3/8” shotty ? ….. unlikely it would …. for the most part …. but folk still win the lottery with 1000000:1 odds …… bad shit happens as well as good shit .

This is where the recommendation that 1/2” is the safest minimum pipe size to use comes from .
However , that still doesn’t negate the potential danger of a wad of botanicals or grains being puked up and crusting up on a layer of mesh or small openings.

Having said that , the first still I built had 3/8” shotty and I still use it for spirit runs on Neutrals and Rums .
But on the odd occasion I use grains , I use my larger 1/2” or 3/4” liebigs

Sieving /straining what goes into your boiler is a good start to being confident wont leave it .

[Steve Broady]

Thank you, Yummyrum! I know that questions like mine must get tiresome to read and answer, but you’ve done a thorough job of explaining exactly what I was hoping to understand. I’m the sort of person that doesn’t mind following rules or taking advice, as long as I can see some sense in it. I just don’t like arbitrary “this is the way it should be for everybody,” when everybody is so unique. Kind of why I’m here and in this hobby in the first place, I suppose!

Taking all the comments and information and advice in, I think I’ll be starting a new condenser build soon. Something that is way to clean, compact enough to store, and large enough to be safer. A Dimroth is high on the list at the moment. I’m curious, has anyone tried building a sectional Liebig? I have ideas…

[shadylane]

... I’m curious, has anyone tried building a sectional Liebig? I have ideas…

I'm curious what a "sectional Liebig" is?

[Ben]

There are some mechanical advantages to half inch tube as well as the safety side... you need 4x the length of 1/4" as you do 1/2" tube to get the same surface area. If you are trying to build a shotgun and keep it short you need a ton of tubes, and fabrication difficulty increases greatly, especially if you are trying to knock down more than a few hundred watts. A Leibig gets crazy on length.

The cost to knock down a watt with 1/2" is probably less than it is with 1/4", if a length of half inch is 2x the cost of 1/4" it is still half as expensive, because its 4x more effective.

A big safety consideration is that you have enough knockdown to be able to push cool distillate, with no risk of pumping vapor out of your still.

Dimroth is a different animal. You can use cheap refrigerator tubing and run multiple inlets/outlets to compensate for the lack of flow.

[jonnys_spirit]

I use 3/4" reduced down to 1/2" for my small alembic maceration still... I wouldn't recommend going smaller - just for safety - even if it may be ok 75% of the time. How many % are you willing to risk for safety?

Cheers,
j

[shadylane]

Since 1/2"id tubing and fittings are commonly used for plumbing, it's more available.
And often cost less than smaller sized copper.

[Steve Broady]

... I’m curious, has anyone tried building a sectional Liebig? I have ideas…

I'm curious what a "sectional Liebig" is?

The way I was picturing it, essentially a number of short Liebigs attached to each other in series. Keep the individual units short enough for easy storage, but assemble it into something long enough o be useful.

[The Baker]

Then there was the time a bug nested in the tube.

Geoff

[shadylane]

Then there was the time a bug nested in the tube.

Geoff

Shit happens.
And it happens more often to those that didn't plan ahead.

[shadylane]

The way I was picturing it, essentially a number of short Liebigs attached to each other in series. Keep the individual units short enough for easy storage, but assemble it into something long enough o be useful.

That sounds like a lot of unnecessary complexity for a stove top still.

[NZChris]

It has been done before to add length to an existing one that was too short. You would have to have a very good reason to go to the trouble of designing and building one from scratch, space constraints maybe?

[shadylane]

... Left to my own devices, and with a pretty healthy respect for my own skin and long standing culture of safety, I would absolutely use 3/8” OD tube without concern.

I’d like to hear the opinions of others, though.

You asked and this isn't the novice section.

How big is the inner diameter of a 3/8" od tube?
I'll tell Ya, it's small enough to be easily plugged up.
And way too small for effectively condensing vapor.

It's your still, so do what you want, but don't be giving fucked up and dangerous advice.
Folks around here want everybody safe, so our hobby can become acceptable and legal....

Now, I'll get off my soap box and get back to drinking.

[Steve Broady]

... Left to my own devices, and with a pretty healthy respect for my own skin and long standing culture of safety, I would absolutely use 3/8” OD tube without concern.

I’d like to hear the opinions of others, though.

You asked and this isn't the novice section.

How big is the inner diameter of a 3/8" od tube?
I'll tell Ya, it's small enough to be easily plugged up.
And way too small for effectively condensing vapor.

It's your still, so do what you want, but don't be giving fucked up and dangerous advice.
Folks around here want everybody safe, so our hobby can become acceptable and legal....

Now, I'll get off my soap box and get back to drinking.

Thank you! That’s exactly why I asked. I want to be safe, I want to make sure I do my best to keep everyone else safe, and if I’m ever in a position to give advice to anyone else, I want to be damn sure that I’m giving good advice. I’ve got a thick enough skin to take whatever roasting I get, and I need to learn. I’m very thankful to guys like yourself who are willing to teach, to share, to correct, and otherwise mentor. This thread has helped me understand the reason for the suggestion, and more to the point it’s helped me understand that the 1/2” recommendation is not just for the guys running stills 4-5 times bigger than mine. And hopefully someone like me will come along in the future with the same question in mind, find this thread, and read it instead of putting himself in danger or annoying anyone else.

[Steve Broady]

The way I was picturing it, essentially a number of short Liebigs attached to each other in series. Keep the individual units short enough for easy storage, but assemble it into something long enough o be useful.

That sounds like a lot of unnecessary complexity for a stove top still.

I’m sure you’re right. It was an idea, but not a good one. The more I thought about it last night, the more reasons I came up with why it wouldn’t be a good solution.

[shadylane]

My bad.
Sorry for sounding like an asshole.
But, the information given was good.

[Steve Broady]

All good, my friend! I’m here to learn. By definition, that means I don’t know enough. Sorry for sounding like I’m trying to bend the rules or cut corners. I promise you, that’s not it at all. I want to donut right, I just like to understand what “right” is and why.

[Steve Broady]

I learned something interesting today, and this seems like the logical place to put it. I finally finished my Dimroth and a spout for it, and added another ferrule to the output end of the shotgun. So I was playing with both of them during a cleaning run.

The shotgun is 1” OD, with 4x1/4” tubes. It’s worked quite well for me so far. The Dimroth is made out of two cocktail shakers, with a coil of 3/8” tubing inside. Both with 1.5” triclamp flanges on each end, so they’re easy to swap out.

With the shotgun in place first, all was going as usual. My still has always shaken just a little while running, which I assumed was because it’s a thin pot and it’s just reacting to the boiling liquid inside. However, because this was a cleaning run, I had the water off and vapor blowing all the way through, and everything was sitting rock steady. As soon as I turned the cooling water on, it started to shake again. I tested this a couple times, and tried the same with the Dimroth.

Turns out, it’s the shotgun making it shake. All I can figure is that the small tubes are completely flooding, even completely vertical, and thus causing the pressure inside the still to fluctuate just enough to set up a vibration.

So to answer my own question a bit, and to confirm what everyone else has said (just in case someone else comes alone after me and has the same question), 1/4” is too small, even if you have 4 of them in parallel. Yes, it works, but it doesn’t work well. That vibration was bad enough at one point to break a solder joint. And now I know that the problem is not my cheap boiler, it’s my undersized condenser.

[shadylane]

Use the 1" for the vapor tube and cool it with 1/4" wrapped around and soldered to the 1"
1 turn every 3" should be enough.
Ya want to get even crazier, have some of the 1/4" running down the inside of the vapor tube.

Something like this.